<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="./js/reg.js"></script>
</head>

<body>
  <form action="" id="sub">
    <div class="root">
      用户名：<input type="text">
      密码：<input type="text">
      <button>提交</button>
  </form>
  <h3>完成了登录功能的优化</h3>
  </div>
  <h3>冲突之前</h3>
  <h4>这是登陆页面的第二版</h4>
  <script>

  </script>
</body>

</html>